Older buildings in Manhattan often have inscriptions on the friezes above their first stories, commemorations of the long-gone companies that built them. A later generation of corporate architecture is similarly associated with defunct or departed firms like Union Carbide and Seagram. The Manhattan skyline is a supersize corporate graveyard. Companies come; they build; they die. Hopefully they hire good architects along the way.

The ever-changing composition of New York City’s private sector is one context in which to digest the news that Amazon is likely to move as many as 25,000 workers to Long Island City, Queens, and Google has plans to acquire space that would allow the Mountain View, California, company to more than double its workforce to nearly 20,000. In the middle of the East River, the campus of Cornell Tech, intended to do for New York what Stanford does for the Bay Area, opened last fall.

It feels like New York became a tech capital overnight.

That’s in part thanks to the brouhaha over Amazon’s HQ2 search. It’s also because, for the first time, New York is starting to see (or at least contemplate) the physical impact of that job growth. For Amazon, that may mean the transformation of a post-industrial area or a rail yard into a corporate campus, following the company’s model in Seattle. For Cornell, it’s a blocky white tower visible from all points south. WeWork recently surpassed JPMorgan Chase to become the city’s largest officeholder with an astounding 5.2 million square feet, planting its logo on buildings citywide.

But the reality is that New York already is a tech capital. Tech-sector employment jumped by 57 percent between 2010 and 2016 to reach nearly 130,000 jobs. Google and Amazon aren’t creating the trend; they’re reacting to it. Proof of the city’s inherent value: Both Google and Facebook say they have built New York headquarters without state subsidies—just as Amazon seeks a break.

One reason you might not have realized this was happening is that most tech companies in New York have operated like Google and Facebook, leasing and renovating space in older buildings rather than creating, like older corporate titans, landmarks of their own. In that way, the boom has been sneaky, taking over New York from inside the buildings that have been here for decades. Amazon may put an end to that trend.

Only San Francisco and San Jose register more tech patents than New York City, and New York state is second behind California in its number of billion-dollar “unicorn” startups.

In a sense, New York City’s success in luring two of the country’s biggest companies to expand marks the success of a long and expensive effort to nurture the tech scene here, whether with subsidies to stop relocations (BuzzFeed, Spotify), straight-up investments like Cornell Tech and the Union Square Tech Hub, or tax breaks to recruit newcomers, which will almost certainly be a part of any Amazon deal.

In the long run, it’s definitely a good thing for New York, with its dependence on income taxes, to secure tens of thousands of new six-figure jobs. The city is in the midst of its largest and longest period of job growth since the Second World War, but that won’t last forever. And it seems particularly smart because of the way that tech is steamrolling other sectors of the economy, some of which have long been important players of New York. Google and Madison Avenue; Amazon and … well, every other business in town. That’s happening whether those companies are here or in Dallas. How long before algorithms come for the city’s tens of thousands of finance jobs?

On a neighborhood level, of course, there’s no arguing that the arrival of big tech offices will change New York neighborhoods forever. Amazon will change Long Island City beyond recognition. Google’s new digs on a relatively isolated stretch of industrial land on the Hudson River ought to quash any lingering fantasies of West Village bohemia.

But San Francisco, Silicon Valley, and Seattle don’t offer a compelling antecedent for what big tech will do in New York, because New York has no parallel among American cities. The Bronx alone is almost twice the size of San Francisco. If 20,000 employees from Amazon and Google arrived overnight, it wouldn’t even amount to a 20 percent increase in the city’s tech jobs. That’s not to say the city and state can’t help manage that influx by protecting existing tenants from their landlords, fixing corruption in the state transportation agency, and allowing the local housing market to meet the need.

But no fundamental spirit of New York lives or dies based on one company arriving—or, thank goodness, one leaving. Just look up!